Referring to the infallible excellence of the Nas album Illmatic, Chillmatic is when the vibe is so good you know things are gonna be chill no matter what happens. It's a laid-back state where nothing can go wrong.

1) Bryan surveyed the party: hot babes and Hennessy. He pronounced it chillmatic.
2) Robert told his friends he would be free all week. Although he had a calculus exam later, he was so ill at math he knew it was going to be chillmatic.